Scientific paper ID 1493 : 2017/3

The problem with the discarded tires and the possibilities for solving it

Despite the understanding that used tires are not hazardous waste, in recent years they have become a major problem for many developed countries. These tires can”t be disposed of and pose a great fire hazard. The accumulated used tires keep water for a long time, making it an ideal mosquito and rodent environment. Therefore, the landfill for the storage of such tires is considered as a danger to public health.

Despite the above, around 10 billion have been accumulated in the world today. Newly-generated 13 to 14 million tonnes are added annually to them. Tires can be recycled at 100%. They consist mainly of rubber, soot, metal, textile. In accordance with the UN Basel Convention (1998) and European Standard CWA 14243 (2002), used tires are not dangerous and harmful when processed, transported and stored properly. There is no special Tire Directive at this stage.

There are several basic ways to manage the BIP:

 Reuse,

 Regeneration,

 Material recycling

 Energy recovery in co-incineration plants:

 Landfilling - according to Directive 199/31 / EC

The recycling of waste tires can be seen in two categories: mechanical recycling and chemical separation of tires with recovery of the different materials from which they are made.

Mechanical recycling and the direct use of scrap granules or whole tires has the advantage that the product finds another application without the need for large investments.

The possibilities for use are many - in asphalt mixes, soft surfaces on playgrounds, anti-erosion, strengthening, drainage facilities and many others. Rubber granules successfully replace new materials such as ethylene-propylene-diene monomer and thermoplastic elastomers in such applications.

Another use of modified rubber materials is found in concrete. Polymer-modified concrete improves the absorption of impact energy and reduces the formation of cracks. Another possibility is to use the rubber granulate in the road surfaces. Rubber asphalt is obtained by a dry or wet process. In dry processes, rubber powder is added directly to the asphalt, and in the wet process the rubber powder is used as a bitumen modifier. The advantages are that the asphalt rubber additives reduce the noise of the vehicles, make the traffic safer in wet conditions and increase the life of the asphalt. Notwithstanding its advantages, this application is still not used in Bulgaria.

In 2009, in Europe, more than 41% of used tires are recovered via recycling, compared with 4% in 1992.